title: Insulin receptor membrane retention by a traceable chimeric mutant.
abstract: BACKGROUND
  The insulin receptor (IR) regulates glucose homeostasis, cell growth and differentiation. It has been hypothesized that the specific signaling characteristics of IR are in part determined by ligand-receptor complexes localization. Downstream signaling could be triggered from the plasma membrane or from endosomes. Regulation of activated receptor's internalization has been proposed as the mechanism responsible for the differential isoform and ligand-specific signaling.
  
  
  RESULTS
  We generated a traceable IR chimera that allows the labeling of the receptor at the cell surface. This mutant binds insulin but fails to get activated and internalized. However, the mutant heterodimerizes with wild type IR inhibiting its auto-phosphorylation and blocking its internalization. IR membrane retention attenuates AP-1 transcriptional activation favoring Akt activation.
  
  
  CONCLUSIONS
  These results suggest that the mutant acts as a selective dominant negative blocking IR internalization-mediated signaling.
authors.affiliation: Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales (FCEN), Universidad de Buenos Aires (UBA) IQUIBICEN, CONICET, Intendente Güiraldes 2160, Ciudad Universitaria, C1428EGA Buenos Aires, Argentina. federico@fbmc.fcen.uba.ar.
authors.forename: Jimena
authors.initials: J
authors.lastname: Giudice
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: Jares-Erijman
authors.forename: Federico Coluccio
authors.initials: FC
authors.lastname: Leskow